484 research outputs found

    A Kinetic Distance-to-Mean Based Routing Algorithm for Vehicular Ad-Hoc Networks

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    Vehicular Ad-hoc Network (VANET) allows vehicles to send information to each other or to roadside equipment in an instant and a wireless manner. It represents a considerable step forward in terms of transportation. Indeed, many applications could benefit from instantly transmitting data such as video and music streaming. Internet connectivity could also be available to the passengers. The main objective and improvement aimed by VANET is a security matter. Warning messages for weather conditions, traffic accidents and fuel consumption instantly transmitted between vehicles would improve road safety. However, one of the critical issues in VANET is the dissemination of messages throughout the network. Indeed, routing algorithms are a key issue because of the high mobility and scalability of VANET compared to other ad-hoc networks. This thesis contributes to the research area by firstly presenting a survey over most of the routing protocol used in VANET and classifying them according to the algorithm used. Secondly, this thesis develops more on the broadcasting algorithm category and particularly on the distance to mean heuristic method that presents good results in terms of reachability and bandwidth consumption. However, distance to mean protocol needs periodic beacons that creates a consequent overhead compared to instant rebroadcasting algorithm. Therefore, this thesis improves this method by reducing overhead using a bio inspired kinetic graph model proposed in the literature. The proposed modified algorithm has been implemented, simulated and evaluated in the network simulator NS3. Results show a lower overhead while preserving a good reachability

    Simulasi Aplikasi Real Time Route Selection berbasis Wireless Sensor Network di Kota Makassar

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    Seiring dengan pertumbuhan kota yang secara di dunia melebihi 50%, persoalan kota menjadi lebih rumit dan kompleks, salah satunya adalah kemacetan yang dapat disebabkan oleh banjir serta pertumbuhan kendaraan yang melebihi luas jalanan. Hal ini juga terjadi di Kota Makassar sebagai ibu kota provinsi Sulawesi Selatan. Saat ini sering terjadi kemacetan lalu lintas di beberapa ruas jalan di Kota Makassar, terutama pada saat peak hours. Data terakhir Juni 2017 menunjukkan jumlah kendaraan di kota Makassar adalah sebanyak 1.425.635 dimana terjadi kenaikan lebih dari 100% dibandingkan tahun 2007. Pada penelitian ini akan dirancang sebuah aplikasi real time route selection dengan memanfaatkan Wireless Sensor Network sebagai penyedia data traffic condition pada ruas jalan. Algoritma pencarian rute terpendek yang digunakan adalah algoritma Dijkstra serta algoritma Floyd-Warshall yang dikombinasikan dengan fungsi skalar Chebycheff. Hasil penelitian menunjukkan bahwa rute yang dihasilkan oleh kedua algoritma sama tetapi algoritma Dijkstra memiliki waktu pemrosesan lebih cepat dengan rerata 7,45 ms. Kelemahan fungsi skalar Chebycheff adalah proses update jarak antar node yang dinamis bergantung pada perubahan kondisi lalu lintas. Hal ini dapat diatasi dengan menggunakan penggunaan metode inferensi lain untuk kriteria kondisi lalu lintas, seperti fuzzy logic maupun metode Multi Criteria Decision Making

    Data center resilience assessment : storage, networking and security.

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    Data centers (DC) are the core of the national cyber infrastructure. With the incredible growth of critical data volumes in financial institutions, government organizations, and global companies, data centers are becoming larger and more distributed posing more challenges for operational continuity in the presence of experienced cyber attackers and occasional natural disasters. The main objective of this research work is to present a new methodology for data center resilience assessment, this methodology consists of: • Define Data center resilience requirements. • Devise a high level metric for data center resilience. • Design and develop a tool to validate and the metric. Since computer networks are an important component in the data center architecture, this research work was extended to investigate computer network resilience enhancement opportunities within the area of routing protocols, redundancy, and server load to minimize the network down time and increase the time period of resisting attacks. Data center resilience assessment is a complex process as it involves several aspects such as: policies for emergencies, recovery plans, variation in data center operational roles, hosted/processed data types and data center architectures. However, in this dissertation, storage, networking and security are emphasized. The need for resilience assessment emerged due to the gap in existing reliability, availability, and serviceability (RAS) measures. Resilience as an evaluation metric leads to better proactive perspective in system design and management. The proposed Data center resilience assessment portal (DC-RAP) is designed to easily integrate various operational scenarios. DC-RAP features a user friendly interface to assess the resilience in terms of performance analysis and speed recovery by collecting the following information: time to detect attacks, time to resist, time to fail and recovery time. Several set of experiments were performed, results obtained from investigating the impact of routing protocols, server load balancing algorithms on network resilience, showed that using particular routing protocol or server load balancing algorithm can enhance network resilience level in terms of minimizing the downtime and ensure speed recovery. Also experimental results for investigating the use social network analysis (SNA) for identifying important router in computer network showed that the SNA was successful in identifying important routers. This important router list can be used to redundant those routers to ensure high level of resilience. Finally, experimental results for testing and validating the data center resilience assessment methodology using the DC-RAP showed the ability of the methodology quantify data center resilience in terms of providing steady performance, minimal recovery time and maximum resistance-attacks time. The main contributions of this work can be summarized as follows: • A methodology for evaluation data center resilience has been developed. • Implemented a Data Center Resilience Assessment Portal (D$-RAP) for resilience evaluations. • Investigated the usage of Social Network Analysis to Improve the computer network resilience

    Routing and mobility strategies for mobile ad hoc networks

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    EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Performance analysis and application development of hybrid WiMAX-WiFi IP video surveillance systems

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    Traditional Closed Circuit Television (CCTV) analogue cameras installed in buildings and other areas of security interest necessitates the use of cable lines. However, analogue systems are limited by distance; and storing analogue data requires huge space or bandwidth. Wired systems are also prone to vandalism, they cannot be installed in a hostile terrain and in heritage sites, where cabling would distort original design. Currently, there is a paradigm shift towards wireless solutions (WiMAX, Wi-Fi, 3G, 4G) to complement and in some cases replace the wired system. A wireless solution of the Fourth-Generation Surveillance System (4GSS) has been proposed in this thesis. It is a hybrid WiMAX-WiFi video surveillance system. The performance analysis of the hybrid WiMAX-WiFi is compared with the conventional WiMAX surveillance models. The video surveillance models and the algorithm that exploit the advantages of both WiMAX and Wi-Fi for scenarios of fixed and mobile wireless cameras have been proposed, simulated and compared with the mathematical/analytical models. The hybrid WiMAX-WiFi video surveillance model has been extended to include a Wireless Mesh configuration on the Wi-Fi part, to improve the scalability and reliability. A performance analysis for hybrid WiMAX-WiFi system with an appropriate Mobility model has been considered for the case of mobile cameras. A security software application for mobile smartphones that sends surveillance images to either local or remote servers has been developed. The developed software has been tested, evaluated and deployed in low bandwidth Wi-Fi wireless network environments. WiMAX is a wireless metropolitan access network technology that provides broadband services to the connected customers. Major modules and units of WiMAX include the Customer Provided Equipment (CPE), the Access Service Network (ASN) which consist one or more Base Stations (BS) and the Connectivity Service Network (CSN). Various interfaces exist between each unit and module. WiMAX is based on the IEEE 802.16 family of standards. Wi-Fi, on the other hand, is a wireless access network operating in the local area network; and it is based on the IEEE 802.11 standards

    都市の持続可能性に向けた旅行行動と知的移動データ統合に関する包括的研究

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    過去数十年にわたり世界中で都市の持続可能性がトレンドとなり研究対象となっている.人々は,非効率な天然資源の消費や社会経済活動による環境破壊など,地球環境に有害な活動を行い,これには都市計画や交通計画を始め,多くの分野が密接に関係している.現在では,これらを解決する新技術の開発や応用が広範囲な研究分野で日々取り組まれている.本研究では観光に関する問題を,交通と都市の研究の観点からさまざまなビックデータを使用し,持続可能な都市開発を目標とした具体的な解決策を示した.本研究では都市や地域の持続可能性に資するデータの活用方法として,Wi-Fiパケットセンサーを使用した旅行者にとって魅力的な観光目的地マネジメントに関する研究,およびETCプローブデータを使用した旅行時間の信頼性の観測における天候の影響に関する分析を組み合わせて示した.本論文では,都市の移動性の認知に対して以下に示す3つの研究から,特徴的な結果と有効な分析手法を確立した.1)Wi-Fiパッケージセンシング調査を使用した,広域観光エリアでの周遊パターンのマイニングベースの関連法則の調査,2)Wi-Fi追跡データでの大規模な観光地の持続可能な開発に向けた魅力的な目的地の抽出,3)ETC2.0プローブデータを使用して,様々な道路タイプを考慮した旅行の信頼性に対する降雪の影響の評価.以上の研究から,複数視点の考察を積み重ね,包括的な評価と提案を行い,いくつかの重要な結果が得られた.この論文の貢献は,より良い社会への問題解決への糸口となり,今後の政策立案者にとって有意義な内容となるだろう.According to sustainability, the trend is spreading out around the world for past decades. There are many area subjects involved, such as city planning, transportation planning, and so on, because people realized human activities harmful to the environment by consuming natural resources with less efficiency process or damage environment by social and economic movements. Currently, emerging technologies considered for the proactive procedure in extensive study areas regarding new technology application and knowledge based. In term of transport and urban study, including tourism concerns, we used intelligent data from deferent sources to be demonstrating the possible solutions which involve sustainable urban development concept. In this study, as a method of utilizing data that contributes to the sustainability of cities and regions, consideration of attractive destination management for tourists by using wireless probe data, and the weather impact on travel time reliability observation by using electronic toll collection probe data, it represented as combination experiments throughout comprehensive study. This dissertation addressed three contribution studies to the composed acknowledgment of urban mobility, and it obtained the intelligent data and specific method of research-based. It consists of; 1) an association rule mining-based exploration of travel patterns in wide tourism areas using a Wi-Fi package sensing survey, 2) Attractive destinations mining towards massive tourism area sustainable development on Wi-Fi tracking data, and 3) Assessment of the impact of snowfall on travel reliability considering different road types using ETC2.0 probe data. Hence, a stack of varying viewpoints researches provided a comprehensive review and suggestion throughout significant results. The contribution of this dissertation could be an advantage substance for strategy and policies planner to recognize alternative solutions leading to a better society.室蘭工業大学 (Muroran Institute of Technology)博士(工学

    Mobile Ad-Hoc Networks

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    Being infrastructure-less and without central administration control, wireless ad-hoc networking is playing a more and more important role in extending the coverage of traditional wireless infrastructure (cellular networks, wireless LAN, etc). This book includes state-of the-art techniques and solutions for wireless ad-hoc networks. It focuses on the following topics in ad-hoc networks: vehicular ad-hoc networks, security and caching, TCP in ad-hoc networks and emerging applications. It is targeted to provide network engineers and researchers with design guidelines for large scale wireless ad hoc networks

    Variable power transmission in highly Mobile Ad-Hoc Networks

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    Mobile Ad Hoc Networks pose challenges in terms of power control, due to their fixed transmission power, the mobility of nodes and a constantly changing topology. High levels of power are needed in wireless networks, particularly for routing. As a result of the increase in the number of communication devices being used, there is the challenge of increased density within these networks, and a need to extend the battery life of communication devices. In order to address this challenge, this thesis presents the development of a new protocol (Dynamic Power AODV), which is an enhancement of the Ad Hoc On Demand Distance Vector (AODV) protocol. The new protocol dynamically adjusts the transmission power based on the range, which depends on node density. This thesis provides a systematic evaluation of the performance of DP-AODV, in a high speed and high density environment, in comparison with three other routing protocols. The experiments demonstrated that DP-AODV performed better than two of the protocols in all scenarios. As compared to the third protocol (AOMDV), DP-AODV gave better performance results for throughput and Power Consumption, but AOMDV performed better in terms of Packet Delivery Fraction rate and End-to-End Delay in some cases
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